Muzzles are used primarily to keep aggressive dogs from biting people or other dogs. Sometimes, though, you can use a muzzle to teach a dog to stop barking. All dogs bark but many do so excessively and inappropriately. If your dog is barking too much, you need to train it to stop. A muzzle is a tool to help you do just that.
Try several muzzles on your dog before you purchase one. Make sure the muzzle fits. Your dog must be able to drink water and pant through the muzzle. Generally, there should be half an inch of space between the dog's nose and the front of the muzzle.
Choose a command to speak in a stern voice whenever your dog is barking inappropriately. "Stop" and "Enough" are good commands to use.
Use your command when your dog starts barking. If the dog does not stop barking, place the muzzle on him. Wait 5 to 10 minutes before taking the muzzle off.
Give your dog a treat if he remains quiet and tell him he is a "good dog." Give him attention when he is doing the right thing. Dogs are people pleasers and will quickly pick up on what makes you happy.
Repeat the process until your dog stops barking when you give your command. At that point, the muzzle is no longer needed.